<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		
	</body>
	<script type="text/javascript">
		var arr = [1,2,3,55,78,90,"小明"];
		var x = "小明";
		if(arr.indexOf(x) == -1){
			arr.push(x)
		}else{
			alert("数组中存在"+x)
		}
		
		arr.splice()
		
	</script>
</html>
